I am concerned Rebecca - why hasn't your GP treated you for vaginal atrophy? Anti-biotics are not for
as-necessary use for any medical condition. Are you in the UK

I would take a list of my symptoms to discuss, then ask for appropriate treatment (we have threads on VA in multiples on here so one can see what a problem it is!) [My Bladder etc. as well as several by SuziQ]
Vaginal atrophy is difficult to control unless caught early. It begins with repeated urine infection-type symptoms: i.e. the need to pee, intense pain in the spincter, need to pee often but not passing much each time. VA is due to the vaginal area drying, = itchiness and aggravation of the whole area: bladder, anus, vagina, vulva ........ whilst ABs do help it is not the answer to this on-going side-effect of menopause. Your GP should by now have sent a fresh urine sample from you to a Hospital Laboratory to be 'grown', so that if necessary the appropriate Anti-biotic can be prescribed.
If there is no growth, then appropriate VA treatment should be prescribed and used appropriately. If you have a Practice Nurse I suggest that you hot-foot it to see her and discuss. Your GP isn't correct in continuing to ignore that your symptoms may be hormonal! ABs should avoided unless absolutely necessary, it is predicted that by I think, 2025, that they will be less useful over-all. Dryness is a typical symptom of menopause which your GP should be aware of, if he/she isn't, then I would go to speak to a Pharmacist - most have private rooms now and are very helpful.
I find that if VA symptoms niggle then an over-the-counter pain relief eases, along with the treatment as prescribed. I can I admit, B a little lazy with treatments

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Then I begin to suffer and it really isn't worth it .........
Aslo, from what I understand, Anti-biotics must be prescribed appropriately and used for a complete course: i.e. 3 days of high strength or 5-10 days dependant upon which bug has been grown. There are 'over-all' [broad spectrum] ABs but these will not be used in future, either for humans or animals.